Dental device



June 1940- G. M. HOLLENBACK g V 9 DENTAL DEVICE IN VENTOR Geo/ye 1y,fizzle/Mack ATTORNEY Patented June 4, 1940 UNITED STATES PATENT- OFFICE3 Claims.

This invention broadly relates to a dental device, and particularly tomeans adapted to triturate amalgams. I

It is common practice by dentists to use in the 5 cavities of teethamalgams of various metals,

particularly where the tooth is not readily observable and aninexpensive filling is desired by the patient. However, amalgams havenot proved entirely satisfactory due to'various causes, among which maybe specifically mentioned, that of contraction. The average amalgam,so-called, consists of mercury and alloy. The alloy varies withdifferent manufacturers, based upon their experience, but generallycontains copper, silver and possibly zinc. It has been found thatparticle size of the filings of the metal alloy may control contractionof the amalgam when the amalgam is triturated. In fact, the subject ofexpansion and contraction of amalgams has been studied -8: over a periodof time. It is possiblev to cause considerablecontraction of the amalgamwhen the amalgam is not properly triturated.

Trituration of an alloy with mercury is usually accomplished in what istermed a mortar through ,5 the medium of a pestle. This pestleisrevolved within the mortar to effect trituration but unless a givenpressure is maintained by the pestle upon the amalgam, varying degreesof contraction may result in the amalgam, irrespective of the given rateof speed at which the pestle is moved over the amalgam. It is ordinarypractice for a dentist to place a drop or more of triple distilledmercury over the alloy and to work the mercury and alloy together, towit, triturate it. After the dentist has reached what to him orexperience teaches is proper trituration, the amalgam. is.

removed from the mortar, usually by rollingthe same into a compact formby the fingers whereupon, in the palm of the hand, the amalgam. ismulled. This is done in order to remove excess mercury and to assure aproper coating of all of the alloy grains with mercury. Usually, themulled. amalgamis rolled into a cylindrical form and out intosmallpieces so that a short cylinder may be placed in the tooth. cavity andthereafter condensed by a-suitable condenser.

Over a period of time, the inventor has made tests for dimensionalchanges, flow and crushing strength of various amalgams, and has foundthat the factors just mentioned can be controlled to a high degree bythe invention to be described. In fact, it is possible for the tyredentist to obtain results comparable to those obtained by the mostexpert dental technician.

Under-trituration will tend to increase expansion and to reduce crushingstrength of an amalgain and to increase flow. Over-trituration will tendto produce shrinkage in the amalgam in direct proportion to the amountof over-trituration, to increase the crushing strength and flow. Correcttrituration will prevent shrinkage and tend to hold expansion withindesirable limits. It will-decrease flow and increase crushing strength.

While I have mentioned mulling of the amalgam in the hand, still I donot recommend this procedure, but prefer to place the amalgam after itsremoval from the mortar in. a small piece of rubber dam and work theamalgam in said dam into a compact mass. The reason for this is that anymethod of manipulation which tends to contaminate the amalgam in anywaymay result in an inferior amalgam.

An object of the present invention is the provision of means wherebycorrect trituration of an amalgam may be obtained.

Another object is the provision of means whereby an amalgam may beformed in such a manner that the result to be obtained from said amalgamin use or service may be accurately predetermined.

Another object is the provision of a device for" use in trituratingamalgams which may be used as readily by an amateur as a professional,the same results being obtained in the amalgam.

Another object is the provision of a device of the character stated,wherein accurate pressure engagement may be maintained on an amalgamduring trituration thereof.

Another object is the provision of a pestle and mortar wherein thepestle may be maintained at a selected pressure engagement with the saidmortar at all times during rotation of the said pestle.

Another object is the provision of suitable means for use in conjunctionwith a pestle and a mortar adapted to receive said pestle whereby atechnician is eifectively prevented from increasing pressure of saidpestle against said mortar during movement thereof.

Other objects of the invention consist of a device which is inexpensivein cost of manufacture, efiicient in operation, capable of performingsuperior results for the purpose intended, is compact and ornamental inappearance, capable of being readily cleaned, easily assembled, and ofgreat utility. I

With the above mentioned and other objects in view, theinvention'consists in the novel and useful provision, formation,construction, association, and relative arrangement of parts, membersand features, all as depicted in a certain embodiment in theaccompanying drawing, described generally, and more particularly pointedout in the claims.

In the drawing:

Figure l is a perspective view of my dental device as an entirety, and,

Figure 2 is a vertical sectional view on the line 22 of Figure 1.

Referring now with particularity to the drawing, I provide a base iwhich may be substan' tially circular in form and provided with ancecentric concavity 2 in the upper surface of said base. This concavityis adapted to have received therein and to hold in position a mortar 3.What is termed a mortar usually comprises a bowl-like receptacle and, inthe present instance, the bowl portion is provided on the inner surfaceof the base with a raised center l. This construction results in theprovision of an annular concavity 5. Adapted for reception within thebowl portion of the mortar and particularly in the concavity 5, is apestle 6. A tubular shank, l, provided with a cap '8, has the capthereof secured to the pestle at its upper end in any ordinary manner.The end opposite the capB carries a socket member 9, the socket portionbeing at iii. Adapted for reception in the socket is ball head H on oneend of a shank i2.

The base i has secured thereto a pedestal i3, such as by having areduced threaded diameter portion threaded into an opening of the base,as indicated at it and an arm i5 secured at the opposite end of thepedestal 3. The arm is provided with a transverse bore adapted toreceive a bushing 56. Through the bushing is passed the shank i2.

Adapted to be carried by the shank i2 is an annular disc I], providedwith an annular cnlargement i8 upon the under stuface thereof,

. which annular enlargement is pinned at 45, or

otherwise secured to the shank E2. The disc ii is adapted to sustain andact as a platform for one or more annular weights, such as shown at 2d,2! and 22. Thus, a constant pressure is exerted by said weights in adownward dlrection to impose a given pressure between the head of thepestle and the concavity 5 of the mortar. Surrounding the shank l is adouble conical spring 23. One end of said spring may be Socured to thecap 8, the other end being free. This spring acts as the handle orfinger-hold for actuating the pestle. By separating the coils of thespring as designated in the drawing, any attempted downward pressure isimmediately absorbed by the spring without in any manner increasing thepressure of the pestle against the mortar.

General directions for actuating mortars and as accepted by dentistseverywhere, is to hold the pestle with a pin grip, and this practiceshould be followed so far as actuation of the pestle is concerned. Inother words, the fingerhold or handle portion 23 should be held with apen grip between the thumb and the first finger.

The operation, uses and advantages of the invention are as follows:

Having a good alloy with known characteristics as furnished by themanufacturer thereof, and assuming the use of triple distilled mercuryand combining the same in the proper proportions as indicated by themanufacturer of the alloy,-

by way of example, this proportion being as 5 to 8, the same is placedwithin the mortar. The

pressure to be exerted by the pestle upon this material may be threepounds and, accordingly, a proper weight is supported upon the platformll. It is known that the number of revolutions of the pestle within themortar greatly affects the characteristics of the amalgam so far as in--crease or decrease of flow, and expansion or pestle is easily revolveddue to the ball and socket arrangement and the weight or weights on theplatform exert a constant downward pressure under gravity influence. Itwill be observed that the ball 8 i is adapted to be directly centeredover the raised center of the mortar.

The device Works exceedingly easily and produces efficient results, asit readily may be seen that lateral and vertical pressures other thanthat exerted downwardly by the weights is effectively overcome by theconstruction described and shown.

It is obvious that various changes and modifications and variations maybe made in practicing the invention in departure from the particularshowing of the drawing and description as given without, however,departing from the true spirit of the invention.

I claim:

1. In a dental device of the character disclosed; a mortar formed with araised center defining an annular pathway; a pestle disposed in saidpathway and guided thereby when moved 2. In a dental device of thecharacter disclosed; a mortar formed with a raised center defining anannularpathway, a pestle disposed in said pathway and guided therebywhen moved therein, weight means, and means slidably guiding the weightmeans along a vertical axis passing through the axis of the raisedcenter of the mortar, and means between the second named means and thepestle'whereby the said weight means exerts a constant downward pressureon said pestle, and a spring finger hold on said pestle through whichthe pestle may be moved in said pathway.

3. In a dental device of the character disclosed; a mortar formed with araised center defining an annular pathway, a pestle disposed in saidpathway and guided thereby when moved therein, weight means, and meansslidably guiding the weight means along a vertical axis passing throughthe axis of the raised center of the mortar, means transmitting theweight against the pestle shank while permitting gyratory motion of saidshank, and a conical. spring on said pestle shank adapted to be held bythe fingers

